Here's a low point, though: after being turned into a radioactive hivemind zombie in Siberia and nearly dying--you should be looking for the trades right now--Captain America is a bit banged up, but still goes with his Avengers co-leader the Wasp, to a briefing with the military on plans for a counterattack against Kang the Conqueror. Seriously, go to Amazon or something, I'll wait. I drag these issues out every so often, and read that whole stretch straight through.
OK, now a higher point: Kang is all but defeated at this point, his armies routed, his massive starship base crash-landed, his personal weapons failing, and his son Marcus sent back to the future to carry on his legacy. But Kang isn't going out without a fight. He knows he's done, but this will cement his name and his honor.
Cap immediately steps up, but before the other Avengers take his back, Thor stops them:
One plot point that had been running for a while, was that when Thor believed Captain America had been killed, Thor was beside himself with rage. (Quicksilver and the Black Knight were also apparently dead, but Thor wasn't so broken up about that. It may have slipped Busiek's mind that Pietro and Dane hate each other, though...) Thor begins to worry that he's going to be too attached to Cap and the other Avengers, most of whom he'll probably see grow old and die. Cap is probably Thor's favorite mortal, though, and here we see why.
The only downside to Busiek's magnum opus? While it is kinda nice that it all takes place in Avengers proper, no spin-offs or one-shots or X-Men vs. Kang series...hell, that might've been fun. It would've at least been something to mention that Kang's invasion was happening on the same planet as the rest of Marvel's books; and there's no magic fix or convenient forgetting in the end. Still, it's a great run, and missed.
And unlike the Avengers books of the last few years, Busiek does it while still fitting in new characters like Silverclaw and Triathalon, not beating you over the head with them, but gradually getting you to like them more and more. (Is Ares the last addition to the Avengers roster? I sure as hell don't count Daken...) I have to wonder if they are remembered fondly, or at all; or if they are as forgotten and maligned as, say, Gypsy or Vibe?
First panel from Avengers #45, "Life During Wartime" Written by Kurt Busiek, "reserve artists" Manuel Garcia and Bob Layton. Kang's beatdown comes in Avengers #54, "A Good Day to Die" Written by Busiek, art by Kieron Dwyer and Rick Remender.